Introduction to the internal structure and advantages and disadvantages of 18650 cylindrical lithium battery cells.
The 18650 cylindrical lithium battery cell is mainly composed of five parts: metal shell, positive electrode, negative electrode, thin film, and electrolyte, each of which plays its own role to ensure normal charging and discharging. The detailed structure is as follows:
Positive electrode: The positive electrode material of 18650 cylindrical lithium battery cells is generally lithium iron phosphate, lithium cobalt oxide, etc. The differences in each positive electrode material will directly affect the characteristics and cost of 18650 lithium batteries.
Negative electrode: The negative electrode materials of 18650 cylindrical lithium battery cells include tin based negative electrode materials, nanoscale negative electrode materials, carbon negative electrode materials, etc. In batteries, negative electrode materials have an oxidizing effect. The relative potential is relatively low.
Electrolyte solution: Taking lithium iron phosphate as an example, it is divided into solute and solvent. Solute: commonly used lithium salts, such as lithium perchlorate, lithium hexafluorophosphate, and lithium tetrafluoroborate. Solvent: Lithium ion batteries often use organic solvents such as ether, ethylene carbonate, propylene carbonate, diethyl carbonate, etc.
Advantages of 18650 cylindrical lithium battery cells
1. Long cycle life: The cycle life of 18650 lithium batteries can reach over 500 times, which is more than twice that of ordinary batteries.
2. Large capacity: The capacity of 18650 cylindrical lithium battery cells is generally between 1200mAh and 3100mAh, and it should be noted that the capacity of general batteries is only about 800. This is just a single 18650 cylindrical lithium battery cell. If combined into an
18650 lithium battery pack, breaking through 5000mAh is not a problem at all.
3. High safety performance: 18650 lithium batteries have separate positive and negative electrodes to prevent battery short circuits. So the possibility of it experiencing a short circuit has been reduced to the extreme. High safety performance, no explosion, no combustion.
4. High voltage: The voltage of 18650 lithium batteries is generally above 3.6 and 3.7, far higher than the 1.2V voltage of nickel cadmium and nickel hydrogen batteries.
5. No memory effect: Charge and discharge as needed, easy to use.
Disadvantages of 18650 cylindrical lithium battery cells
1. Stability: Compared to polymer lithium batteries, 18650 lithium batteries are prone to short circuits or explosions.
2. Cannot overcharge: 18650 lithium batteries require protective circuits to prevent the battery from being overcharged and discharging.
3. High cost: The production conditions required for 18650 lithium batteries are high, which undoubtedly increases production costs.
